JP2020064820A - Thermal radiation light source - Google Patents

Abstract

To provide a thermal radiation light source which can be installed while a substrate and a thermal radiation layer are exposed in the atmosphere and which has a large emissivity in a wavelength of a narrow band equal to or less than 4 μm and has a small emissivity in a wavelength equal to or larger than 4 μm.SOLUTION: The thermal radiation light source is provided in which a thermal radiation layer N and a substrate K heating the thermal radiation layer N are laminated. The thermal radiation layer N is configured in a configuration in which a radiation control part Na and a transparent oxide layer Nb for emission are laminated in the form of arranging the radiation control part Na having an MIM lamination part M locating a transparent oxide layer R for resonance formed in the transparent oxide between platinum layers P arranged along the direction of lamination and the transparent oxide layer Nb for emission formed in the transparent oxide on the side closer to the substrate K in this order. The transparent oxide layer R for resonance has a thickness in which the wavelength equal to or less than 4 μm is the resonance wavelength.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a thermal radiation light source in which a thermal radiation layer and a substrate that heats the thermal radiation layer are laminated.

Such a heat radiation light source heats the heat radiation layer to a high temperature on the substrate, thereby radiating radiant light for heating an object to be heated from the heat radiation layer.
As such a heat radiation light source, a substrate and a heat radiation layer are disposed in a sealed state inside a sealed tube formed of a translucent airtight member such as quartz glass, and the inside of the sealed tube is evacuated. Alternatively, a sealed tube may be filled with an inert gas such as nitrogen gas (see, for example, Patent Document 1).

  In Patent Document 1, the substrate is made of a refractory metal such as tungsten that generates heat when an electric current is applied, and the heat radiation layer is formed of a metal layer such as tantalum or molybdenum. By disposing the sealing tube inside the sealing tube, deterioration of the substrate and the heat radiation layer due to oxidation is prevented.

JP, 2015-138638, A

  In the conventional thermal radiation light source, the substrate and the thermal radiation layer are disposed inside the sealing tube in a sealed state, so that the entire structure is complicated and expensive, so that the substrate and the thermal radiation layer are exposed to the atmosphere. There is a demand for a thermal radiation light source that can be installed in an exposed state.

Further, for example, for heating an object to be heated through quartz glass like a heating lamp, a large emissivity (emission) is obtained at a narrow band wavelength of 4 μm or less (that is, a narrow band wavelength of mid-infrared light or less). There is a demand for a thermal radiant light source that has a high emissivity and a small emissivity (emissivity) for wavelengths larger than 4 μm (that is, far infrared light).
That is, for example, when far-infrared light having a wavelength larger than 4 μm is emitted when heating an object to be heated through the quartz glass, the quartz glass absorbs the far-infrared light and reaches a high temperature. Therefore, a large-scale equipment for cooling the glass is required, and the equipment for heating the object to be heated housed inside the quartz glass tube becomes complicated.

  The present invention has been made in view of the above circumstances, and an object thereof is to install the substrate and the heat radiation layer in the state of being exposed to the atmosphere, and to provide a large radiation in a narrow band wavelength of 4 μm or less. The present invention is to provide a thermal radiant light source having a high emissivity and a low emissivity for wavelengths larger than 4 μm.

The thermal radiation light source of the present invention is one in which a thermal radiation layer and a substrate for heating the thermal radiation layer are laminated, and the characteristic configuration thereof is:
The heat radiation layer includes a MIM stacking portion that positions a transparent oxide layer for resonance formed of a transparent oxide between a pair of platinum layers arranged along the stacking direction of the heat radiation layer and the substrate. A state in which the radiation control unit and the radiation transparent oxide layer are laminated in a form in which the radiation control unit and the radiation transparent oxide layer formed of the transparent oxide are sequentially located on the side closer to the substrate. Is composed of
The thickness of the transparent oxide layer for resonance is a thickness having a resonance wavelength of 4 μm or less.

  That is, the heat radiation layer is formed by stacking the radiation control unit and the radiation transparent oxide layer in such a manner that the radiation control unit including the MIM layered portion and the radiation transparent oxide layer are located in this order on the side closer to the substrate. When the heat radiation layer is heated to a high temperature state by the substrate, the radiation control section including the MIM laminated section emits radiation light, and the radiation light is transparently oxidized for radiation. It will be emitted from the physical layer.

The substrate which is in a high temperature state to heat the thermal radiation layer emits radiant light, but the platinum layer adjacent to the substrate in the MIM laminated portion of the radiation control unit shields the radiant light of the substrate and Since the radiant light is prevented from passing through the inside of the radiation control unit, the radiant light of the substrate is suppressed from affecting the radiant light emitted from the radiation control unit.
Further, the radiation transparent oxide layer having a smaller refractive index than platinum and a larger refractive index than air is located adjacent to the platinum layer located on the side where the radiation transparent oxide layer in the radiation control section is present, The reflectance of the platinum layer located on the side where the radiation transparent oxide layer is present is reduced, and the radiant light emitted from the radiation control unit can be favorably emitted to the outside.

  The MIM stacking unit included in the radiation control unit positions the resonance transparent oxide layer between a pair of platinum layers arranged in the stacking direction of the heat radiation layer and the substrate, and is transparent for resonance. Since the thickness of the oxide layer has a resonance wavelength of 4 μm or less, the wavelength of 4 μm or less of radiation emitted from the platinum layer heated to a high temperature state (that is, mid-infrared). Since a narrow band wavelength of light or less) is amplified by the resonance effect, the radiant light emitted from the radiation control unit has a narrow band wavelength of 4 μm or less (for example, a wavelength of 0.8 μm or more and less than 2.5 μm). It has a large emissivity (near-infrared light) in the near-infrared light and a narrow band wavelength including the wavelength of 2.5 μm or more and 4 μm or less of the mid-infrared light, and has a wavelength larger than 4 μm (that is, far infrared light ) Has a small emissivity (emissivity), As a result, the amplified radiant light with a narrow band wavelength of 4 μm or less is emitted to the outside from the radiation transparent oxide layer.

  In addition, the MIM means a metal insulator metal, and the MIM laminated portion is configured so that the radiant light having a wavelength of 4 μm or less among the radiant light emitted by the platinum layer is generated between the heat radiating layer and the substrate. By repeatedly reflecting between the platinum layers arranged in the stacking direction (in the transparent oxide layer for resonance), the radiated light with a wavelength of 4 μm or less is amplified, and the amplified radiation with a wavelength of 4 μm or less is amplified. Light will be emitted out of the emissive transparent oxide layer.

  That is, the radiant light having a wavelength of 4 μm or less is amplified while being repeatedly reflected between the platinum layers arranged along the stacking direction of the thermal radiation layer and the substrate, and a part of the radiant light having a wavelength of 4 μm or less is emitted. The light is transmitted to the side where the transparent oxide layer is present and is emitted to the outside from the radiation transparent oxide layer. As a result, the amplified radiation light having a wavelength of 4 μm or less is emitted. Will be released from the outside.

On the other hand, a wavelength larger than 4 μm of the radiant light emitted from the platinum layer is emitted to the outside from the radiation transparent oxide layer in a state where it is less likely to be amplified by the resonance effect. .
As a result, the radiant light emitted outside from the transparent oxide layer for emission has a large emissivity (emissivity) at a narrow band wavelength of 4 μm or less (that is, a narrow band wavelength of mid-infrared light or less). However, it has a small emissivity (emissivity) at a wavelength larger than 4 μm (that is, a wavelength of far infrared light).

  The platinum layer adjacent to the substrate among the plurality of platinum layers provided in the MIM laminated portion needs to shield the radiated light from the substrate, and the other platinum layers need to transmit part of the radiated light. As a result, the platinum layer adjacent to the substrate will be formed thicker than the other platinum layers.

  As described above, the heat radiation layer causes amplified radiation light having a wavelength of 4 μm or less to be emitted to the outside from the radiation transparent oxide layer. In addition, even when the heat radiation layer is installed in the air, the radiation control unit and By suppressing the deterioration of the substrate due to oxidation, the optical characteristics can be maintained for a long time.

In other words, the platinum layer of the MIM laminated portion is formed of platinum, and since the standard Gibbs oxidation energy is positively large in all temperature ranges and platinum does not oxidize in air, it is installed in air. However, it does not deteriorate due to oxidation.
Further, even when the transparent oxide layer for radiation and the transparent oxide layer for resonance are formed of a material that oxidizes the substrate in order to prevent oxygen in the air from permeating toward the substrate. Therefore, the deterioration of the substrate due to oxidation is suppressed for a long time.
Therefore, even if the heat radiation layer is installed in the air, the optical characteristics can be maintained for a long time.

  By the way, the platinum forming the platinum layer adjacent to the substrate may flow and aggregate on the substrate when heated to a high temperature, but the transparent transparent oxide layer for resonance has a function of suppressing the movement of platinum. Platinum that forms the platinum layer adjacent to the resonance transparent oxide layer on the side where the radiation transparent oxide layer is present with respect to the resonance transparent oxide layer is heated to a high temperature. Although there is a risk of fluidizing above and aggregating, the transparent oxide layer for radiation exerts the action of suppressing the movement of platinum, and therefore, it is possible to inhibit the agglomeration of platinum. The layer will be able to maintain the optical properties for a long time.

  In short, according to the characteristic configuration of the present invention, the substrate and the heat radiation layer can be installed in a state of being exposed to the atmosphere, and moreover, they have a large emissivity in a narrow band wavelength of 4 μm or less and a wavelength larger than 4 μm. It is possible to provide a thermal radiation light source having a low emissivity.

  A further characteristic configuration of the thermal radiation light source of the present invention is that the radiation control unit is configured to include a plurality of MIM stacking units.

  That is, since a plurality of MIM laminated portions for arranging the transparent transparent oxide layer for resonance are provided between the pair of platinum layers arranged along the laminating direction of the heat radiation layer and the substrate, amplification by resonance action is sufficient. By being exerted, radiant light having a wavelength of 4 μm or less can be appropriately amplified.

  Incidentally, the provision of a plurality of MIM laminated portions means that three or more platinum layers arranged along the laminating direction of the heat radiation layer and the substrate are provided, and the transparent transparent oxidation for resonance is provided between adjacent ones of the platinum layers. It means a form in which a physical layer is located.

Note that, for example, a configuration in which three platinum layers arranged along the stacking direction of the heat radiation layer and the substrate are provided, and the transparent transparent oxide layer for resonance is positioned between adjacent platinum layers, that is, 2 In the configuration in which two MIM laminated portions are provided, the radiant light is reflected between the adjacent platinum layers and also reflected between the platinum layers located at both ends in the laminating direction of the thermal radiation layer and the substrate. It will be amplified while being processed.
That is, when three or more platinum layers are provided along the stacking direction of the heat radiation layer and the substrate, in addition to repeatedly reflecting the radiant light between the adjacent platinum layers, another platinum layer The effect of repeatedly reflecting the radiant light is exhibited even between the platinum layers positioned so as to sandwich the above.

  In the case where a plurality of MIM laminated portions are provided, the resonance frequency of each MIM laminated portion is changed to obtain amplified radiation light having a wavelength of 4 μm or less and a wavelength of 0.8 μm or more and less than 2.5 μm. In addition to the near-infrared light and the mid-infrared light having a wavelength of 2.5 μm or more and 4 μm or less, for example, visible light having a wavelength of 0.4 μm or more and less than 0.8 μm can be obtained. Of less than 0.4 can be obtained.

  In short, according to the further characteristic configuration of the thermal radiation light source of the present invention, it is possible to appropriately amplify the radiation light having a wavelength of 4 μm or less.

  A further characteristic configuration of the thermal radiation light source of the present invention is that an adhesion layer for a substrate is laminated between the substrate and the platinum layer adjacent to the substrate in the radiation control section.

  That is, since the substrate adhesion layer is laminated between the substrate and the platinum layer adjacent to the substrate in the radiation control unit, the radiation control unit peels off from the substrate when the radiation control unit is heated by the substrate. Can be suppressed.

  That is, since the thermal expansion coefficient of the substrate and the thermal expansion coefficient of the radiation control unit in which a plurality of thin films are laminated are different, the radiation control unit may peel off from the substrate when the radiation control unit is heated by the substrate. However, the adhesion between the substrate and the platinum layer adjacent to the substrate in the radiation control unit can be enhanced by the adhesion layer for the substrate, and thus the radiation control unit can be prevented from peeling off from the substrate.

  In short, according to the further characteristic configuration of the thermal radiation light source of the present invention, it is possible to suppress the radiation control section from peeling off from the substrate.

  A further characteristic configuration of the thermal radiation light source of the present invention is the space between the platinum layer and the resonance transparent oxide layer in the MIM laminated portion, and the radiation in the radiation transparent oxide layer and the radiation control portion. An adhesion layer for platinum is laminated between each of the platinum layers adjacent to the transparent oxide layer for platinum.

  That is, the adhesion layer for platinum is between the platinum layer and the transparent oxide layer for resonance in the MIM laminated portion, and the platinum layer adjacent to the transparent oxide layer for radiation and the transparent oxide layer for radiation in the radiation control section. Since the radiation control section is heated to a high temperature by the substrate, it is possible to prevent the platinum layer in the MIM stacking section from flowing and aggregating due to the difference in thermal expansion coefficient. It is possible to suppress the peeling of the platinum layer and the resonant transparent oxide layer and the peeling of the radiation transparent oxide layer and the platinum layer.

  That is, since the adhesion between platinum and the transparent oxide is low, when the radiation control unit is heated to a high temperature on the substrate, the platinum layer adjacent to the resonance transparent oxide layer or the radiation transparent oxide layer is Adjacent platinum layers may flow and aggregate, but by stacking an adhesion layer for platinum, adhesion of the platinum layer adjacent to the resonance transparent oxide layer to the resonance transparent oxide layer and radiation The adhesion of the platinum layer adjacent to the transparent oxide layer for radiation to the transparent oxide layer for radiation is increased, so that the platinum layer in the MIM laminated portion flows when the radiation control unit is heated to a high temperature state by the substrate. Therefore, it is possible to suppress the agglomeration of the platinum layer and the resonance transparent oxide layer from peeling off, and the radiation transparent oxide layer and the platinum layer from peeling off.

  In short, according to the further characteristic configuration of the thermal radiation light source of the present invention, when the radiation control unit is heated to a high temperature state by the substrate, it is possible to prevent the platinum layer in the MIM laminated unit from flowing and aggregating.

  A further characteristic configuration of the heat radiation light source of the present invention is that the substrate adhesion layer and the platinum adhesion layer are made of titanium.

  That is, titanium is adjacent to the substrate for adhesion of the platinum layer adjacent to the substrate to the substrate, adhesion of the platinum layer adjacent to the resonance transparent oxide layer to the resonance transparent oxide layer, and adjacent to the radiation transparent oxide layer. Since the adhesion of the platinum layer to the transparent oxide layer for radiation can be enhanced satisfactorily, and the melting point is as high as 1668 ° C., when the radiation control unit is heated to a high temperature state by the substrate, the MIM It is possible to appropriately suppress the platinum layers in the laminated portion from flowing and aggregating.

Incidentally, the titanium forming the adhesion layer for the substrate and the adhesion layer for platinum may be gradually oxidized into titanium oxide due to the use of the thermal radiation light source in the atmosphere. In other words, when the thermal radiation source is used in the atmosphere, it can be considered that the substrate adhesion layer and the platinum adhesion layer are formed of titanium oxide.
However, the titanium forming the adhesion layer for the substrate and the adhesion layer for platinum does not all change to titanium oxide, but the titanium in the part that adheres to the platinum layer does not oxidize and the titanium that adheres to the platinum layer does not oxidize. The state (metal state) will be continued.

  The adhesion layer for the substrate and the adhesion layer for platinum, which are made of titanium, are formed in a thin film state so as to have light transmittance, and the titanium formed in such a thin film is oxidized. Although it will be changed to titanium, since titanium oxide has transparency, even if titanium is changed to titanium oxide, it does not adversely affect the performance of the heat radiation layer.

  In short, according to the further characteristic configuration of the thermal radiation light source of the present invention, when the radiation control unit is heated to a high temperature state by the substrate, it is possible to appropriately suppress the platinum layer in the MIM laminated unit from flowing and aggregating. it can.

  A further characteristic configuration of the thermal radiation light source of the present invention is that the transparent oxide forming the resonance transparent oxide layer and the radiation transparent oxide layer is aluminum oxide or titanium oxide.

  That is, since aluminum oxide and titanium oxide have a small oxygen diffusion coefficient, by using aluminum oxide or titanium oxide as the transparent oxide forming the transparent oxide layer for radiation and the transparent oxide layer for resonance, Even when the substrate is made of a material that oxidizes by appropriately suppressing the permeation of oxygen, it is possible to prevent the surface of the substrate on the side where the radiation control section is laminated from being deteriorated by oxidation. Can be avoided appropriately.

  In short, according to the further characteristic configuration of the thermal radiation light source of the present invention, it is possible to appropriately avoid deterioration of the surface of the substrate on the side where the radiation control section is laminated due to oxidation.

  A further characteristic configuration of the thermal radiation light source of the present invention is that the substrate is configured to generate heat by energization.

  That is, since the substrate is configured to self-heat when energized, the substrate can be self-heated by energizing the substrate to heat the radiation control unit. Since it is not necessary to provide a special external heating unit for heating, the overall configuration can be simplified.

  Incidentally, examples of the material that self-heats when energized include metal materials such as Kanthal and Nichrome, and the substrate can be formed of these materials.

  In short, according to the further characteristic configuration of the thermal radiation light source of the present invention, the overall configuration can be simplified.

  A further characteristic configuration of the thermal radiation light source of the present invention is that the substrate is configured to be heated by an external heating unit.

That is, since the substrate is heated by the external heating unit, the substrate can be formed using various materials such as quartz (silicon dioxide) and sapphire.
That is, the substrate can be made of a non-oxidizing material such as quartz (silicon dioxide) or sapphire, and the oxidative deterioration of the substrate can be appropriately suppressed.

  In short, according to the further characteristic configuration of the thermal radiation light source of the present invention, oxidative deterioration of the substrate can be appropriately suppressed.

Diagram showing the basic configuration of the thermal radiation light source Table showing a structural example in the basic configuration of the thermal radiation light source Graph showing the relationship between the structural example of the thermal radiation light source and the radiation spectrum The figure which shows another form in the basic composition of a thermal radiation light source. A graph showing the relationship between another form of the basic configuration of the thermal radiation light source and the radiation spectrum. Graph showing the relationship between the type of transparent oxide of the thermal radiation light source and the radiation spectrum The figure which shows the concrete structure of a thermal radiation light source Diagram showing changes in transparent oxide layer for resonance Graph showing the relationship between the thickness of the platinum adhesion layer and the radiation spectrum A graph showing the relationship between the change in the transparent oxide layer for resonance and the radiation spectrum. Graph showing the relationship between the thickness of the first platinum layer and the radiation spectrum Graph showing the relationship between the thickness of the second platinum layer and the radiation spectrum Graph showing the relationship between the thickness of the second platinum layer and the radiation spectrum Graph showing the relationship between the thickness of the transparent oxide layer for resonance and the radiation spectrum A graph showing the relationship between the thickness of the transparent oxide layer for resonance and the absorption spectrum. A perspective view showing the relationship between a heat radiation light source and a heating electrode. A perspective view showing the relationship between a heat radiation light source and a heating electrode. A perspective view showing a relationship between a heat radiation light source and a heat radiation body. A perspective view showing a relationship between a heat radiation light source and a high temperature fluid source Diagram showing the thermal radiation light source of the reference example

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[Basic configuration of thermal radiation light source]
FIG. 1 shows a basic configuration of the heat radiation light source Q. The heat radiation light source Q is configured in a form in which a heat radiation layer N and a substrate K for heating the heat radiation layer N are stacked. .
The heat radiation layer N and the radiation transparent oxide layer Nb formed of a transparent oxide are arranged in this order on the side closer to the substrate K in the order of the radiation control portion Na and the radiation transparent oxide layer Nb. The object layers Nb are laminated.

The radiation control unit Na positions the transparent transparent oxide layer R formed of a transparent oxide between a pair of platinum layers P arranged in the stacking direction of the thermal radiation layer N and the substrate K to form a MIM stack. It is configured to include the part M.
The thickness of the transparent transparent oxide layer R is set to have a resonance wavelength of 4 μm or less.

In the basic configuration of the thermal radiation light source Q shown in FIG. 1, the radiation control section Na includes one MIM laminated section M.
That is, in the basic configuration of the thermal radiation light source Q, the platinum layer P, the resonance transparent oxide layer R, the platinum layer P, and the radiation transparent oxide layer Nb that form the MIM laminated portion M are described in this description. In this order, they are sequentially stacked on the substrate K.
In the following description, the platinum layer P adjacent to the substrate K in the MIM laminated portion M is referred to as the first platinum layer P1, and the platinum layer P adjacent to the radiation transparent oxide layer Nb in the MIM laminated portion M is referred to as the platinum layer P. , Second platinum layer P2.

Then, the heat radiation layer N is configured to emit radiation light H from the heat radiation layer N by heating the heat radiation layer N to a high temperature state (for example, 800 ° C.) on the substrate K.
Specifically, as the radiant light H, a narrow band wavelength of 4 μm or less (for example, near-infrared light having a wavelength of 0.8 μm or more and less than 2.5 μm and mid-infrared light having a wavelength of 2.5 μm or more and 4 μm or less It emits radiant light H having a large emissivity (emissivity) at a narrow band wavelength including light and a small emissivity (emissivity) at a wavelength larger than 4 μm (that is, far infrared light). Is configured.

  That is, when the heat radiation layer N is heated to a high temperature state (for example, 800 ° C.) on the substrate K, the platinum layer P (first platinum layer P1 and second platinum layer P1) in the MIM laminated portion M included in the radiation control unit Na is provided. P2) emits radiant light, and the emissivity (emissivity) of the radiant light (radiant light from platinum) is directed to a short wavelength at a wavelength of 4 μm or less as shown in FIG. Will tend to gradually increase, and a low value will be maintained at wavelengths larger than 4 μm.

  Since the resonant transparent oxide layer R included in the MIM laminated portion M has a thickness having a resonance wavelength of 4 μm or less, the platinum layer P of the MIM laminated portion M (first platinum layer P1 and The wavelength of 4 μm or less (that is, the wavelength of the narrow band of the mid-infrared light) of the radiant light of the second platinum layer P2) is amplified by the resonance action, and as a result, the radiation controller Na has the narrow band of 4 μm or less. Emissivity (emissivity) at a wavelength (for example, a narrow band wavelength including near-infrared light having a wavelength of 0.8 μm or more and less than 2.5 μm and mid-infrared light having a wavelength of 2.5 μm or more and 4 μm or less) ) And having a small emissivity (emissivity) at a wavelength larger than 4 μm (that is, far infrared light), and as a result, the amplified radiant light H having a wavelength of 4 μm or less is transparent for emission. It is released from the oxide layer Nb to the outside.

  In addition, MIM means a metal insulator metal, and the MIM laminated portion M is 4 μm or less of the radiated light of the platinum layer P (first platinum layer P1 and second platinum layer P2). 4 μm or less by repeatedly reflecting radiant light of a wavelength between a pair of platinum layers P (first platinum layer P1 and second platinum layer P2) arranged along the stacking direction of the thermal radiation layer N and the substrate K. The amplified radiant light having a wavelength of 4 μm or less is emitted to the outside from the transparent oxide layer for emission Nb.

  That is, radiated light having a wavelength of 4 μm or less is amplified while being repeatedly reflected between the platinum layers P (first platinum layer P1 and second platinum layer P2) arranged along the stacking direction of the thermal radiation layer N and the substrate K. Then, a part of the radiant light having a wavelength of 4 μm or less is transmitted to the existing side of the radiation transparent oxide layer Nb and is emitted to the outside from the radiation transparent oxide layer Nb. The amplified radiation light having a wavelength of 4 μm or less is emitted to the outside from the radiation transparent oxide layer Nb.

On the other hand, of the radiation emitted by the platinum layer P (first platinum layer P1 and second platinum layer P2), radiation with a wavelength greater than 4 μm is less likely to be amplified by resonance. , From the transparent oxide layer for radiation to the outside.
As a result, the radiant light H emitted from the thermal radiant light source Q (radiant light emitted to the outside from the radiation transparent oxide layer Nb) has a wavelength in a narrow band of 4 μm or less (that is, a narrow wavelength of mid infrared light or less). It has a large emissivity (emissivity) at a wavelength of a band) and a small emissivity (emissivity) at a wavelength larger than 4 μm (that is, a wavelength of far infrared light).

  By the way, radiant light is radiated from the substrate K which is in a high temperature state for heating the thermal radiative layer N, but transmission of the radiant light to the radiation control section Na is blocked by the first platinum layer P1. Will be. In other words, the thickness of the first platinum layer P1 is a thickness that can shield the radiation light from the substrate K.

  In addition, since the radiation transparent oxide layer Nb has a higher refractive index than platinum and a smaller refractive index than air, the platinum layer P (second platinum layer) located on the side where the radiation transparent oxide layer Nb exists. Since the reflectance of P2) is reduced, the radiant light emitted from the radiation control unit Na can be favorably emitted to the outside.

  Of the platinum layers P (first platinum layer P1 and second platinum layer P2) provided in the MIM laminated portion M, the platinum layer P (first platinum layer P1) adjacent to the substrate K is the radiation of the substrate K. The other platinum layer P (second platinum layer P2) needs to transmit a part of the radiant light, so that the platinum layer P (first platinum layer P1) adjacent to the substrate K is , The platinum layer adjacent to the substrate K of the platinum layer P (first platinum layer P1 and second platinum layer P2) because it is formed thicker than the other platinum layer P (second platinum layer P2). The radiation intensity of P (first platinum layer P1) is higher than that of other platinum layers P (second platinum layer P2).

  By the way, the thermal radiation light source Q of the present invention "has a large emissivity of 4 μm or less, and the maximum emissivity between 0.8 μm and 4 μm (near infrared to mid-infrared region) is 90% or more. The radiation peak in the far infrared region of 4 μm or more is small and does not have the peak of the emissivity ”(hereinafter referred to as an appropriate configuration).

[Explanation of structural example of basic configuration]
Next, a structural example of the basic configuration of the thermal radiation light source Q will be described. In the structural example described below, the transparent oxide forming the radiation transparent oxide layer Nb and the resonance transparent oxide layer R is alumina (aluminum oxide, Al ₂ O ₃ ). Any substrate can be used as the substrate K, but details of the substrate K will be described later.

  The structural examples described below are four examples of structure 1 to structure 4 as shown in the table of FIG. In the table of FIG. 2, the substrate K is the layer No1, the first platinum layer P1 is the layer No2, the resonance transparent oxide layer R is the layer No3, the second platinum layer P2 is the layer No4, and the radiation transparent oxide layer. Nb is described as Layer No. 5.

  As shown in FIG. 3, the thermal radiation light source Q having the structures 1 to 4 has near-infrared light having a wavelength of 0.8 μm or more and less than 2.5 μm and mid-infrared light having a wavelength of 2.5 μm or more and 4 μm or less. The radiant light H has a large emissivity (emissivity) at a narrow band of wavelengths including and has a small emissivity (emissivity) at a wavelength larger than 4 μm (that is, far infrared light).

  When the thickness (thickness) of the resonance transparent oxide layer R of the layer No. 3 is thin, the resonance frequency is shortened, so the peak position of the emissivity is on the short wavelength side, and the resonance transparency of the layer No. 3 is transparent. When the thickness (thickness) of the oxide layer R is large, the resonance frequency has a long wavelength, and therefore the emissivity peak tends to move to a long wavelength.

When the film thickness (thickness) of the second platinum layer P2 of the layer No4 is thick, the peak of the spectrum of the emissivity is narrowed, and the film thickness (thickness) of the second platinum layer P2 of the layer No4 is thin. In this case, the peak of the emissivity spectrum tends to be broadened.
Furthermore, as the film thickness (thickness) of the radiation transparent oxide layer Nb of the layer No. 5 increases, the emissivity spectrum tends to move to the long wavelength side.

When the thermal radiation light source Q has the above-mentioned proper configuration, the preferable range of the film thickness (thickness) of the first platinum layer P1 is, for example, 10 nm or more, and the film thickness (thickness of the second platinum layer P2 is The preferable range of () is, for example, 1.5 nm or more and 18 nm or less.
Hereinafter, the suitable range of the film thickness (thickness) of the first platinum layer P1 and the second platinum layer P2 will be described.

FIG. 11 illustrates the relationship between the film thickness (thickness) of the first platinum layer P1 and the emissivity in the thermal radiation light source Q having the structure 2. When the film thickness (thickness) of the first platinum layer P1 is changed to 5 to 150 nm and the film thickness (thickness) of the first platinum layer P1 is 5 nm, the peak of the emissivity is 90%. Although it does not exceed, the peak of emissivity exceeds 90% in the case of 10 nm.
Further, when the film thickness (thickness) of the first platinum layer P1 is increased, the radiation spectrum does not gradually change, and the radiation spectrum is almost fixed when the film thickness (thickness) is around 60 nm. As described above, there is no upper limit to the regulation of the film thickness (thickness) of the first platinum layer P1.
From the above results, the preferable range of the film thickness (thickness) of the first platinum layer P1 is, for example, 10 nm or more.

FIG. 12 illustrates the relationship between the film thickness (thickness) of the second platinum layer P2 and the emissivity. However, in FIG. 12, when the thickness of the first platinum layer P1 is 150 nm, the thickness of the transparent oxide layer for resonance R1 is 140 nm, and the thickness of the transparent oxide layer for radiation Nb is 75 nm, the second platinum is The radiation spectrum when the film thickness (thickness) of the layer P2 is changed to 1 nm, 1.5 nm, and 6 nm is illustrated.
When the thickness of the second platinum layer P2 is thicker than 1.5 nm, the peak of emissivity exceeds 90%, but when it is thinner than that, the peak of emissivity does not exceed 90%.

FIG. 13 illustrates the relationship between the film thickness (thickness) of the second platinum layer P2 and the emissivity. However, FIG. 13 shows the case where the thickness of the first platinum layer P1 is 150 nm, the thickness of the first resonance transparent oxide layer R1 is 140 nm, and the thickness of the radiation transparent oxide layer Nb is 100 nm. It is a radiation spectrum when the film thickness (thickness) of 2 platinum layer P2 is changed to 6 nm, 15 nm, 18 nm, and 25 nm.
When the thickness of the second platinum layer P2 is 19 nm, the peak of the emissivity is 90%, and when it is thicker than 19 nm, the peak of the emissivity is small.
From the above results, the preferable range of the film thickness (thickness) of the second platinum layer P2 is, for example, 1.5 nm or more and 18 nm or less.

In the case where the thermal radiation light source Q has the above-mentioned proper configuration, the preferable range of the thickness (film thickness) of the transparent transparent oxide layer R for resonance having a resonance wavelength of 4 μm or less is that the transparent oxide is alumina (Al ₂ When it is O ₃ ), it is 60 nm or more and 1050 nm or less.
Hereinafter, a suitable range of the thickness (film thickness) of the resonance transparent oxide layer R formed of alumina (Al ₂ O ₃ ) will be described.

FIG. 14 shows the relationship between the thickness (film thickness) of the resonant transparent oxide layer R and the emissivity of the thermal radiation light source Q. However, FIG. 14 shows that when the thickness of the first platinum layer P1 is 150 nm, the thickness of the second platinum layer P2 is 6.6 nm, and the thickness of the radiation transparent oxide layer Nb is 94 nm, the resonance transparent The radiation spectrum when the film thickness (thickness) of the oxide layer R is changed to 40 nm, 60 nm, 80 nm, and 100 nm is illustrated.
It can be seen from FIG. 14 that the lower limit of the film thickness (thickness) of the transparent transparent oxide layer R for resonance at which the emissivity at a peak of 800 nm is 90% or more is 60 nm.

FIG. 15 shows the relationship between the thickness (film thickness) of the resonant transparent oxide layer R and the emissivity of the thermal radiation light source Q. However, FIG. 15 shows that when the thickness of the first platinum layer P1 is 150 nm, the thickness of the second platinum layer P2 is 10 nm, and the thickness of the radiation transparent oxide layer Nb is 100 nm, the resonance transparent oxide. The radiation spectrum when the film thickness (thickness) of the layer R is changed to 800 nm, 1050 nm, and 1200 nm is illustrated.
From FIG. 15, it can be seen that when the thickness (thickness) of the transparent transparent oxide layer R for resonance becomes thicker than 1050 nm, a peak of the emissivity appears in a long wave region (far infrared region) longer than 4000 nm.
As a result, when the transparent oxide is alumina (Al ₂ O ₃ ), the preferable range of the thickness (film thickness) of the transparent oxide layer for resonance R having a resonance wavelength of 4 μm or less is 60 nm or more and 1050 nm. It is the following.

By the way, the preferable range of the thickness (film thickness) of the transparent oxide layer for resonance R changes depending on the refractive index of the transparent oxide.
The lower limit of the preferred range is
(Lower limit of film thickness for each material (unit: nm)) = − 30.4n + 108. Note that n is the refractive index of each material.
The upper limit of the preferred range is
(Upper limit of film thickness for each material (unit: nm)) = − 600n + 2030. Note that n is the refractive index of each material.

  By the way, in the case where the thermal radiation light source Q has the above-mentioned proper configuration, a preferable range of the film thickness (thickness) of the transparent oxide layer Nb for radiation of the layer No. 5 is, for example, 50 nm or more and 500 nm or less.

  As described above, FIG. 3 shows the radiation spectrum of platinum (platinum only). By comparing the radiation spectrum of platinum (platinum only) with the radiation spectra of structure 1 to structure 4, It can be seen that the emissivity is increased in the infrared to mid-infrared region, and the contrast between the high emissivity portion and the low emissivity portion is increased.

[Another form of basic configuration]
In the above-described basic configuration, the radiation control unit Na includes one MIM stacking unit M, but the radiation control unit Na may include a plurality of MIM stacking units M.
It is to be noted that the provision of a plurality of MIM laminated portions M means that three or more platinum layers P arranged in the lamination direction of the heat radiation layer N and the substrate K are provided, and the platinum layers P are arranged between adjacent ones. It means a form in which the transparent oxide layer R for resonance is positioned.

FIG. 4 exemplifies a case where the radiation control unit Na includes two MIM laminated units M, and hereinafter, the exemplified thermal radiation light source Q is referred to as a structure 5.
The structure 5 has, as the platinum layer P, a first platinum layer P1 adjacent to the substrate K, a second platinum layer P2 adjacent to the transparent radiation oxide layer Nb, and a first platinum layer P1 and a second platinum layer P2. It has a third platinum layer P3 located in between.

As the resonance transparent oxide layer R, the first resonance transparent oxide layer R1 located between the first platinum layer P1 and the third platinum layer P3, and the second platinum layer P2 and the third platinum layer P3. And a second transparent transparent oxide layer R2 for resonance.
In Structure 5, the transparent oxide forming the radiation transparent oxide layer Nb and the resonance transparent oxide layer R is alumina (Al ₂ O ₃ ). Any substrate can be used as the substrate K, but details of the substrate K will be described later.

  Then, one MIM laminated part M is composed of the first platinum layer P1, the third platinum layer P3, and the first resonance transparent oxide layer R1, and the second platinum layer P2, the third platinum layer P3, and One MIM laminated portion M is configured from the second transparent transparent oxide layer R2, and as a result, the radiation control unit Na includes two MIM laminated portions M.

In Structure 5, the thickness of the first platinum layer P1 is 150 nm, the thickness of the first resonance transparent oxide layer R1 is 65 nm, the thickness of the third platinum layer P3 is 8 nm, and the second resonance transparent oxide layer R2. 5 shows a radiation spectrum in the case where the thickness of the second platinum layer P2 is 5 nm and the thickness of the transparent oxide layer for radiation Nb is 72 nm.
In addition, the radiation spectrum of the above-mentioned structure 1 is also shown in FIG.

  In the structure 5, since the resonance frequencies of the two MIM laminated portions M are changed, as shown in FIG. 5, it becomes possible to resonate even in the wavelength of visible light having a wavelength of 0.4 μm or more and less than 0.8 μm. As the radiated light H having a wavelength of 4 μm or less, a wavelength of 0 μm is added to near-infrared light having a wavelength of 0.8 μm or more and less than 2.5 μm and mid-infrared light having a wavelength of 2.5 μm or more and 4 μm or less. Radiation light H including visible light having a wavelength of 0.4 μm or more and less than 0.8 μm and ultraviolet light having a wavelength of less than 0.4 is obtained.

[Type of transparent oxide]
In the above basic configuration of the thermal radiation light source Q and another mode of the basic configuration, the case where the transparent oxide forming the radiation transparent oxide layer Nb and the resonance transparent oxide layer R is alumina (Al ₂ O ₃ ). Although illustrated, examples of the transparent oxide include tantalum pentoxide (Ta ₂ O ₅ ), silicon dioxide (SiO ₂ ), niobium pentoxide (Nb ₂ O ₅ ), magnesium oxide (MgO), titanium oxide (TiO ₂ ), Hafnium oxide (HfO ₂ ) or the like can be used.
Since alumina (Al ₂ O ₃ ) and titanium oxide (TiO ₂ ) have a small oxygen diffusion coefficient, they are particularly useful as transparent oxides for forming the radiation transparent oxide layer Nb and the resonance transparent oxide layer R. preferable.

  FIG. 6 illustrates a radiation spectrum when the transparent oxide is different in the above-mentioned basic configuration. That is, the thickness of the first platinum layer P1 is 150 nm, the thickness of the resonance transparent oxide layer R is 120 nm, the thickness of the second platinum layer P2 is 8 nm, and the thickness of the radiation transparent oxide layer Nb is 120 nm. In such a case, the radiation spectrum will be exemplified when the transparent oxides forming the radiation transparent oxide layer Nb and the resonance transparent oxide layer R are different.

As shown in FIG. 6, tantalum pentoxide (Ta ₂ O ₅ ), silicon dioxide (SiO ₂ ), and niobium pentoxide are used as transparent oxides forming the radiation transparent oxide layer Nb and the resonance transparent oxide layer R. Even with (Nb ₂ O ₅ ), magnesium oxide (MgO), titanium oxide (TiO ₂ ), or hafnium oxide (HfO ₂ ), the amplified radiant light H having a wavelength of 4 μm or less can be emitted.

[Specific configuration of thermal radiation light source]
As a specific configuration of the thermal radiation light source Q, as shown in FIG. 7, the substrate adhesion layer S1 is provided between the substrate K and the platinum layer P (first platinum layer P1) adjacent to the substrate K in the radiation control unit Na. Are laminated, and between the platinum layer P (first platinum layer P1 and second platinum layer P2) and the transparent oxide layer R for resonance in the MIM laminated portion M, and the transparent oxide layer Nb for radiation and radiation. The adhesion layer S2 for platinum is laminated between the platinum layer P (second platinum layer P2) adjacent to the radiation transparent oxide layer Nb in the control unit Na.

  That is, since the substrate adhesion layer S1 is laminated between the substrate K and the platinum layer P (first platinum layer P1) adjacent to the substrate K in the radiation control unit Na, the radiation control unit Na is attached to the substrate K. The radiation controller Na is prevented from peeling off from the substrate K when heated by heating.

  That is, since the coefficient of thermal expansion of the substrate K and the coefficient of thermal expansion of the radiation control unit Na in which a plurality of thin films are laminated are significantly different, when the radiation control unit Na is heated by the substrate K, the radiation control unit Na changes. Although there is a risk of peeling from the substrate K, the adhesion between the substrate K and the platinum layer P (first platinum layer P1) adjacent to the substrate K in the radiation control unit Na is enhanced by the substrate adhesion layer S1. This prevents the radiation control unit Na from peeling off from the substrate K.

  Moreover, the platinum adhesion layer S2 is provided between the platinum layer P (first platinum layer P1 and second platinum layer P2) and the resonance transparent oxide layer R in the MIM laminated portion M, and the radiation transparent oxide layer. Since it is provided between Nb and the platinum layer P (second platinum layer P2) adjacent to the radiation transparent oxide layer Nb in the radiation controller Na, the radiation controller Na is heated to a high temperature on the substrate K. At this time, the platinum layer P (first platinum layer P1 and second platinum layer P2) in the MIM laminated portion M is prevented from flowing and aggregating, and the platinum layer P and the transparent oxide layer R for resonance are separated. Peeling off and peeling between the platinum layer P and the radiation transparent oxide layer Nb are suppressed.

  That is, since the adhesion between the platinum and the transparent oxide is low, when the radiation control section Na is heated to a high temperature state on the substrate K, the platinum layer P adjacent to the resonant transparent oxide layer R and the transparent radiation layer are arranged. Although the platinum layer P adjacent to the oxide layer Nb may flow and aggregate, the platinum adhesion layer S2 is laminated, so that the resonance transparent platinum layer P adjacent to the resonance transparent oxide layer R is transparent. By increasing the adhesion to the oxide layer R and the adhesion of the platinum layer P adjacent to the radiation transparent oxide layer Nb to the radiation transparent oxide layer Nb, the radiation control unit Na is in a high temperature state on the substrate K. When heated to a high temperature, the platinum layer P in the MIM laminated portion M is prevented from flowing and aggregating.

  Titanium (Ti) and chromium (Cr) are excellent materials for forming the substrate adhesion layer S1 and the platinum adhesion layer S2 from the viewpoint of melting point and adhesion. In particular, titanium (Ti) is desirable. Hereinafter, it is assumed that the substrate adhesion layer S1 and the platinum adhesion layer S2 are made of titanium (Ti).

  That is, titanium (Ti) adheres to the substrate K of the platinum layer P (first platinum layer P1) adjacent to the substrate K and the platinum layer P (first platinum layer P1) adjacent to the resonant transparent oxide layer R. And adhesion of the second platinum layer P2) to the transparent transparent oxide layer R, and adhesion of the platinum layer P (second platinum layer P2) adjacent to the transparent transparent oxide layer Nb to the transparent transparent oxide layer Nb. Since the melting point is as high as 1668 ° C. and the radiation control section Na is heated to a high temperature state on the substrate K, the platinum layer P (first The first platinum layer P1 and the second platinum layer P2) can be appropriately suppressed from flowing and aggregating.

[Thickness of adhesion layer for substrate]
When the substrate adhesion layer S1 is in a high temperature state, it emits radiation light having a wavelength larger than 4 μm (that is, far-infrared light), but the radiation light emitted from the substrate adhesion layer S1 is Since it is shielded by the platinum layer P1, there is no problem in this regard even if the thickness (film thickness) of the substrate adhesion layer S1 is large.
However, if the substrate adhesion layer S1 is too thick, when the radiation control unit Na is heated to a high temperature state on the substrate K, titanium (Ti) moves around by heat, and the transparent transparent oxide for resonance of the first platinum layer P1. There is a possibility that a phenomenon may appear on the surface where the layer R is present. When such a phenomenon occurs, the heat radiation control structure of the radiation control unit Na collapses, and it becomes difficult to control the heat radiation.

Further, if the substrate adhesion layer S1 is too thin, it becomes impossible to cope with the difference between the thermal expansion coefficient of the radiation control unit Na including a plurality of thin films and the thermal expansion coefficient of the substrate K, and the radiation control unit Na is in a high temperature state on the substrate K. The radiation control unit Na may be peeled off from the substrate K when heated to above.
From such a viewpoint, the thickness of the adhesion layer S1 for substrate (thickness of titanium) is preferably 2 nm or more and 15 nm or less.

[Platinum adhesion layer thickness]
The thickness (film thickness) of the platinum adhesion layer S2 needs to be set from two viewpoints of optical property and durability.
That is, if the adhesion layer S2 for platinum (thickness) is too thick, it is not optically good. That is, when the platinum adhesion layer S2 is in a high temperature state, it emits radiant light having a wavelength larger than 4 μm (that is, far infrared light). Therefore, the thickness (film thickness) of the platinum adhesion layer S2 is If the thickness is too thick, the intensity of the radiated light from the platinum adhesion layer S2 increases, and the radiated light from the radiation control unit Na has a small emissivity (emission) at a wavelength larger than 4 μm (that is, far infrared light). Rate) is adversely affected.

Further, if the adhesion layer S2 for platinum (thickness) is too thick, it blocks radiant light, so it is necessary to avoid that the adhesion layer S2 for platinum (thickness) is too thick. . If it becomes too thick, the peak of the emissivity of 4 μm or less becomes 90% or less.
However, the adhesion layer S2 for platinum does not bring the substrate K and the thin film into close contact, but brings the thin films into close contact with each other. Therefore, even if it is thinner than the adhesion layer S1 for substrate, an adhesion effect is obtained.
From such a viewpoint, the thickness (film thickness) of the platinum adhesion layer S2 is preferably 0.1 nm or more and 10 nm or less.

FIG. 9 shows the relationship between the thickness (film thickness) of the platinum adhesion layer S2 and the emissivity (emissivity) of the thermal radiation light source Q.
In FIG. 9, the substrate adhesion layer S1 has a thickness of 7 nm, the first platinum layer P1 has a thickness of 150 nm, the resonant transparent oxide layer has a thickness of 120 nm, and the second platinum layer P2 has a thickness of 6 nm. In the case where the thickness of the radiation transparent oxide layer Nb is 120 nm, the thickness (film thickness) of the platinum adhesion layer S2 is changed.
From consideration of FIG. 9, it can be seen that the far infrared light on the wavelength side longer than 4 μm increases as the thickness (film thickness) of the platinum adhesion layer S2 increases.

[About oxidation of titanium]
Titanium (Ti) forming the substrate adhesion layer S1 and the platinum adhesion layer S2 is likely to be gradually oxidized and converted to titanium oxide (TiO ₂ ) by using the thermal radiation light source Q in the atmosphere. . In other words, when the thermal radiation light source Q is used in the atmosphere, it can be considered that the substrate adhesion layer S1 and the platinum adhesion layer S2 are formed of titanium oxide (TiO ₂ ). it can.

However, as shown in FIG. 8, the titanium forming the adhesion layer S2 for platinum does not entirely change to titanium oxide, but the titanium in the area which adheres to the platinum layer P (second platinum layer P2) is oxidized. Without being performed, the state of titanium (metal state) in close contact with the platinum layer P (second platinum layer P2) is continued.
Although illustration is omitted, all of the titanium forming the substrate adhesion layer S1 does not change to titanium oxide, but the titanium in the area of adhesion to the platinum layer P (first platinum layer P1) is oxidized. Instead, the state of titanium (metal state) in close contact with the platinum layer P (first platinum layer P1) is continued.

  That is, all of the titanium forming the substrate adhesion layer S1 and the platinum adhesion layer S2 are not changed to titanium oxide, and the titanium at the portion that adheres to the platinum layer P is not oxidized and the platinum layer P is not oxidized. The state of titanium that adheres to the substrate will be continued, and the functions of the substrate adhesive layer S1 and the platinum adhesive layer S2 will continue.

In addition, platinum (Pt) does not react with oxygen because the standard Gibbs oxide energy change is +200 k / mol / O _2. (Chemical reaction proceeds in the direction where the Gibbs energy change becomes negative. Gibbs A positive energy change means no reaction.) This means that it is difficult to use the oxide as an adhesion layer of platinum (Pt) due to the bond energy. From this, when titanium is changed to titanium oxide by oxidation, there is a concern that it will not work as an adhesion layer of platinum (Pt). However, in reality, even if titanium is oxidized, titanium at the interface with platinum (Pt) Since the bond with platinum is maintained, the functions as the substrate adhesion layer S1 and the platinum adhesion layer S2 continue.

By the way, the substrate adhesion layer S1 and the platinum adhesion layer S2 made of titanium are formed in a thin film state so as to have light transmittance, and the titanium formed in the thin film state is titanium oxide. However, since titanium oxide has transparency, even if titanium is changed to titanium oxide, the performance of the heat radiation layer N is not adversely affected.
Considering that the materials forming the substrate adhesion layer S1 and the platinum adhesion layer S2 are oxidized, chromium (Cr) becomes black when oxidized, and therefore, the chromium which becomes black when oxidized is from the viewpoint of radiation control. Titanium (Ti), which is not suitable as an adhesion layer and forms titanium oxide (TiO ₂ ) that becomes transparent when oxidized, is excellent in terms of radiation control.

By the way, if the titanium (Ti) of the platinum adhesion layer S2 is oxidized with time, even if the platinum adhesion layer S2 is thick, the heat radiation when the thickness (film thickness) of FIG. It is thought to approach. However, if the thickness (film thickness) is large, when the radiation control unit Na is heated to a high temperature state on the substrate K, titanium (Ti) moves around by heat and appears on the surface of the second platinum layer P2. This may cause a phenomenon. When such a phenomenon occurs, the heat radiation control structure of the radiation control unit Na collapses, and it becomes difficult to control the heat radiation. Especially, since the platinum of the second platinum layer P2 is thin, the movement of titanium (Ti) greatly affects the collapse of the thermal radiation control structure.
Therefore, it is desirable that the thickness (film thickness) of the platinum adhesion layer S2 be about sub-nm (about 1 nm or less).

[Aging of the heat radiation source]
FIG. 10 shows a temporal change of the thermal radiation spectrum when the actually manufactured thermal radiation light source Q is heated to 800 ° C. in the atmosphere and used.
Incidentally, in FIG. 10, sapphire is used for the substrate K, the thickness of the adhesion layer S1 for the substrate is 7 nm, the thickness of the first platinum layer P1 is 150 nm, the thickness of the transparent oxide layer for resonance is 120 nm, and the second platinum is The thermal radiation spectrum of the thermal radiation light source Q when the thickness of the layer P2 is 6 nm, the thickness of the radiation transparent oxide layer Nb is 120 nm, and the thickness of the platinum adhesion layer S2 is 0.5 nm is illustrated. Is.

  As shown in FIG. 20, although the substrate K, the substrate adhesion layer S1, the first platinum layer P1, the platinum adhesion layer S2, the resonance transparent oxide layer R, and the second platinum layer P2 are provided, If the platinum adhesion layer S2 on the surface of the platinum layer P2 on the side where the radiation transparent oxide layer Nb is present and the radiation transparent oxide layer Nb are omitted, the platinum (Pt) of the second platinum layer P2 is heated during the heating process. ) Agglomerated and began to scatter light, which made it impossible to properly emit radiant light.

As shown in FIG. 10, the thermal radiation spectrum heated for 120 hours (5 days) and the thermal radiation spectrum heated for 24 hours (1 day) are substantially the same.
The thermal radiation spectrum immediately after film formation and the thermal radiation spectrum after heating for 24 hours and 120 hours are different, because the heating increased the crystallinity of alumina (Al ₂ O ₃ ) and platinum (Pt). This is considered to be the cause.

The theoretical value (calculated value) of the heat radiation spectrum is calculated using the optical constant of alumina (Al ₂ O ₃ ) having high crystallinity.
The thermal radiation spectrum immediately after film formation deviates from the theoretical (calculated) thermal radiation spectrum, but the thermal radiation spectrum after heating is extremely close to the theoretical (calculated) thermal radiation spectrum. Therefore, the crystallinity of alumina (Al ₂ O ₃ ) and platinum (Pt) is increased by heating, and the optical constants of alumina (Al ₂ O ₃ ) and platinum (Pt) are close to the theoretical values. Conceivable.

As described above, the thermal radiation light source Q of the present invention is a thermal radiation light source that can be heated to about 800 ° C. in the atmosphere and used.
The melting point of the constituent material of the thermal radiation light source Q of the present invention is 1768 ° C. for platinum (Pt), 2072 ° C. for alumina (Al ₂ O ₃ ), 1668 ° C. for titanium (Ti), and titanium oxide (TiO 2). ₂ ) is 1843 ° C., and the thermal radiation layer N of the thermal radiation light source Q of the present invention is durable up to a temperature of about 1400 ° C., although it depends on the melting point of the substrate K.

[About substrate]
In view of the fact that the thermal radiation light of the substrate K that is in a high temperature state is shielded by the first platinum layer P1 and does not permeate to the radiation control unit Na, the material (base material) of the substrate K is quartz (SiO ₂ ), Sapphire, stainless steel (SUS), Kanthal, nichrome, aluminum, silicon, and various other materials can be used.

There is no particular problem when the substrate K made of an oxide material is used. However, when the substrate K made of a metal material is used and heated in the atmosphere for use, the oxidative deterioration of the substrate K becomes a problem. However, the presence of the transparent oxide layer R for resonance and the transparent oxide layer Nb for radiation prevents oxidative deterioration of the surface of the substrate K on the side where the heat radiation layer N exists, as described above. Become.
The surface of the substrate K on the side where the heat radiation layer N exists is formed as a mirror surface that does not cause irregular reflection.

The substrate K may be configured to self-heat upon energization, or may be configured to be heated by the external heating unit U.
That is, when the substrate K is made of a material such as Kanthal or Nichrome that generates heat when energized, the substrate K can be configured to self-heat when energized.
When the substrate K is made of quartz (SiO ₂ ), sapphire, stainless steel (SUS), or the like, as shown in FIGS. 16 to 19, it is configured to be heated by the external heating unit U.

16 and 17 show a case where the external heating unit U is configured as a plate-shaped heating electrode Ud including a heater wire that generates heat when energized, and the substrate K of the thermal radiation light source Q is in close contact with the heating electrode Ud. It is installed in.
Note that FIG. 17 shows a case where the heat radiation light source Q is arranged on one side of the heating electrode Ud, and FIG. 16 illustrates a case where the heat radiation light source Q is arranged on both sides of the heating electrode Ud. .

FIG. 18 shows a case where the external heating unit U is configured as a thermal radiation source Ug that radiates thermal radiation light G whose wavelength is not controlled, and the substrate K of the thermal radiation light source Q faces the thermal radiation source Ug. It is arranged in a state where it does.
FIG. 19 shows a case where the external heating unit U is configured as a fluid supply source Ut that supplies the high-temperature fluid T, and the substrate K of the thermal radiation light source Q is arranged so as to face the fluid supply source Ut. There is.

[Modification of adhesion layer for substrate]
The substrate adhesion layer S1 is made of titanium (Ti) as described above, but its configuration needs to be slightly changed depending on the type of material forming the substrate K.
When the material forming the substrate K is sapphire or alumina (Al ₂ O ₃ ), the substrate adhesion layer S1 is composed of only titanium (Ti) as described above.

When the material forming the substrate K is quartz (SiO ₂ ), the substrate adhesion layer S1 may be only titanium (Ti), or a laminate of titanium (Ti) and alumina (Al ₂ O ₃ ). It may be structured. In other words, it may be formed by laminating in this order of the first platinum layer P1 / titanium (Ti) / alumina _{(Al 2 O 3) (30nm} ) / substrate K.

When the material forming the substrate K is stainless steel (SUS), canthal, nichrome, aluminum, or silicon, the first platinum layer P1 / titanium (Ti) / alumina (Al ₂ O ₃ ) (30 nm) / substrate K Or the first platinum layer P1 / titanium (Ti) / alumina (Al ₂ O ₃ ) (30 nm) / hafnium oxide (HfO ₂ ) / substrate K in this order.
That is, when the substrate K is a metal or a semiconductor, the first platinum layer P1 / titanium (Ti) may react with the substrate K to form an alloy, which makes it impossible to control radiation. Therefore, from the viewpoint of preventing alloying, it is preferable to insert an oxide layer between the substrate K and titanium (Ti).

[Another embodiment]
Other embodiments will be listed below.
(1) In the above embodiment, even if the back surface of the substrate K opposite to the surface on which the heat radiation layer N is laminated is oxidized, if the thickness of the substrate K is large, the heat radiation layer N is adversely affected. In view of the fact that the heat radiation layer N is laminated on the substrate K, the back surface of the substrate K opposite to the surface on which the heat radiation layer N is laminated is exposed. May be laminated.

(2) In the above embodiment, the radiation control unit Na includes one MIM stacking unit M and two MIM stacking units M, but the radiation control unit Na includes three or more MIM stacking units M. You may implement.

  Note that the configurations disclosed in the above-described embodiments (including other embodiments, the same applies below) can be applied in combination with the configurations disclosed in other embodiments, as long as no contradiction occurs. The embodiments disclosed in the present specification are exemplifications, and the embodiments of the present invention are not limited thereto, and can be appropriately modified within a range not departing from the object of the present invention.

K substrate N thermal radiation layer Na radiation control part Nb radiation transparent oxide layer M MIM laminated part P platinum layer R resonance transparent oxide layer S1 substrate adhesion layer S2 platinum adhesion layer

Claims (8)

A thermal radiation light source in which a thermal radiation layer and a substrate for heating the thermal radiation layer are laminated,
The heat radiation layer includes a MIM stacking portion that positions a transparent oxide layer for resonance formed of a transparent oxide between a pair of platinum layers arranged along the stacking direction of the heat radiation layer and the substrate. In a form in which the radiation control unit and the radiation transparent oxide layer formed of a transparent oxide are sequentially located on the side closer to the substrate, the radiation control unit and the radiation transparent oxide layer are laminated. Composed,
A thermal radiation light source in which the thickness of the transparent oxide layer for resonance is such that a resonance wavelength is a wavelength of 4 μm or less.   The thermal radiation light source according to claim 1, wherein the radiation control unit is configured to include a plurality of the MIM laminated units.   The thermal radiation light source according to claim 1 or 2, wherein a substrate adhesion layer is laminated between the substrate and the platinum layer adjacent to the substrate in the radiation control unit.   Between the platinum layer and the transparent oxide layer for resonance in the MIM laminated part, and between the transparent oxide layer for radiation and the platinum layer adjacent to the transparent oxide layer for radiation in the radiation control part. The thermal radiation light source according to claim 3, wherein a platinum adhesion layer is laminated in each of the spaces.   The thermal radiation light source according to claim 4, wherein the adhesion layer for the substrate and the adhesion layer for platinum are made of titanium.   The thermal radiation light source according to any one of claims 1 to 5, wherein the transparent oxide forming the resonant transparent oxide layer and the radiation transparent oxide layer is aluminum oxide or titanium oxide.   The thermal radiation light source according to any one of claims 1 to 6, wherein the substrate is configured to self-heat when energized.   The thermal radiation light source according to claim 1, wherein the substrate is configured to be heated by an external heating unit.

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